“...or are you suggesting immunological naievete in Europe”
Since the vast majority of the population of Europe didn’t come from Europe, but from Eurasia, that’s highly unlikely.
If the Muslims came from Arabia and Africa, is there the possibility?
I’m openly admitting I have no idea either way, and have never studied enough even to make an educated guess.
...which is why (as they say on Jeopardy) I phrased my response in the form of a question.